2 * linux/kernel/power/user.c
4 * This file provides the user space interface for software suspend/resume.
6 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
8 * This file is released under the GPLv2.
12 #include <linux/suspend.h>
13 #include <linux/syscalls.h>
14 #include <linux/reboot.h>
15 #include <linux/string.h>
16 #include <linux/device.h>
17 #include <linux/miscdevice.h>
19 #include <linux/swap.h>
20 #include <linux/swapops.h>
23 #include <linux/compat.h>
24 #include <linux/console.h>
25 #include <linux/cpu.h>
26 #include <linux/freezer.h>
28 #include <asm/uaccess.h>
33 #define SNAPSHOT_MINOR 231
35 static struct snapshot_data {
36 struct snapshot_handle handle;
41 bool platform_support;
45 atomic_t snapshot_device_available = ATOMIC_INIT(1);
47 static int snapshot_open(struct inode *inode, struct file *filp)
49 struct snapshot_data *data;
54 if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
59 if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
60 atomic_inc(&snapshot_device_available);
64 nonseekable_open(inode, filp);
65 data = &snapshot_state;
66 filp->private_data = data;
67 memset(&data->handle, 0, sizeof(struct snapshot_handle));
68 if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
69 /* Hibernating. The image device should be accessible. */
70 data->swap = swsusp_resume_device ?
71 swap_type_of(swsusp_resume_device, 0, NULL) : -1;
72 data->mode = O_RDONLY;
73 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
75 pm_notifier_call_chain(PM_POST_HIBERNATION);
78 * Resuming. We may need to wait for the image device to
81 wait_for_device_probe();
84 data->mode = O_WRONLY;
85 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
87 error = create_basic_memory_bitmaps();
88 data->free_bitmaps = !error;
91 pm_notifier_call_chain(PM_POST_RESTORE);
94 atomic_inc(&snapshot_device_available);
98 data->platform_support = false;
101 unlock_system_sleep();
106 static int snapshot_release(struct inode *inode, struct file *filp)
108 struct snapshot_data *data;
113 data = filp->private_data;
114 free_all_swap_pages(data->swap);
116 pm_restore_gfp_mask();
117 free_basic_memory_bitmaps();
119 } else if (data->free_bitmaps) {
120 free_basic_memory_bitmaps();
122 pm_notifier_call_chain(data->mode == O_RDONLY ?
123 PM_POST_HIBERNATION : PM_POST_RESTORE);
124 atomic_inc(&snapshot_device_available);
126 unlock_system_sleep();
131 static ssize_t snapshot_read(struct file *filp, char __user *buf,
132 size_t count, loff_t *offp)
134 struct snapshot_data *data;
136 loff_t pg_offp = *offp & ~PAGE_MASK;
140 data = filp->private_data;
145 if (!pg_offp) { /* on page boundary? */
146 res = snapshot_read_next(&data->handle);
150 res = PAGE_SIZE - pg_offp;
153 res = simple_read_from_buffer(buf, count, &pg_offp,
154 data_of(data->handle), res);
159 unlock_system_sleep();
164 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
165 size_t count, loff_t *offp)
167 struct snapshot_data *data;
169 loff_t pg_offp = *offp & ~PAGE_MASK;
173 data = filp->private_data;
176 res = snapshot_write_next(&data->handle);
180 res = PAGE_SIZE - pg_offp;
183 res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
188 unlock_system_sleep();
193 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
197 struct snapshot_data *data;
201 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
203 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
205 if (!capable(CAP_SYS_ADMIN))
208 if (!mutex_trylock(&pm_mutex))
211 lock_device_hotplug();
212 data = filp->private_data;
216 case SNAPSHOT_FREEZE:
220 printk("Syncing filesystems ... ");
224 error = freeze_processes();
228 error = create_basic_memory_bitmaps();
236 case SNAPSHOT_UNFREEZE:
237 if (!data->frozen || data->ready)
239 pm_restore_gfp_mask();
240 free_basic_memory_bitmaps();
241 data->free_bitmaps = false;
243 data->frozen = false;
246 case SNAPSHOT_CREATE_IMAGE:
247 if (data->mode != O_RDONLY || !data->frozen || data->ready) {
251 pm_restore_gfp_mask();
252 error = hibernation_snapshot(data->platform_support);
254 error = put_user(in_suspend, (int __user *)arg);
255 data->ready = !freezer_test_done && !error;
256 freezer_test_done = false;
260 case SNAPSHOT_ATOMIC_RESTORE:
261 snapshot_write_finalize(&data->handle);
262 if (data->mode != O_WRONLY || !data->frozen ||
263 !snapshot_image_loaded(&data->handle)) {
267 error = hibernation_restore(data->platform_support);
272 memset(&data->handle, 0, sizeof(struct snapshot_handle));
275 * It is necessary to thaw kernel threads here, because
276 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
277 * SNAPSHOT_FREE. In that case, if kernel threads were not
278 * thawed, the preallocation of memory carried out by
279 * hibernation_snapshot() might run into problems (i.e. it
280 * might fail or even deadlock).
282 thaw_kernel_threads();
285 case SNAPSHOT_PREF_IMAGE_SIZE:
289 case SNAPSHOT_GET_IMAGE_SIZE:
294 size = snapshot_get_image_size();
296 error = put_user(size, (loff_t __user *)arg);
299 case SNAPSHOT_AVAIL_SWAP_SIZE:
300 size = count_swap_pages(data->swap, 1);
302 error = put_user(size, (loff_t __user *)arg);
305 case SNAPSHOT_ALLOC_SWAP_PAGE:
306 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
310 offset = alloc_swapdev_block(data->swap);
312 offset <<= PAGE_SHIFT;
313 error = put_user(offset, (loff_t __user *)arg);
319 case SNAPSHOT_FREE_SWAP_PAGES:
320 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
324 free_all_swap_pages(data->swap);
333 * Tasks are frozen and the notifiers have been called with
334 * PM_HIBERNATION_PREPARE
336 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
340 case SNAPSHOT_PLATFORM_SUPPORT:
341 data->platform_support = !!arg;
344 case SNAPSHOT_POWER_OFF:
345 if (data->platform_support)
346 error = hibernation_platform_enter();
349 case SNAPSHOT_SET_SWAP_AREA:
350 if (swsusp_swap_in_use()) {
353 struct resume_swap_area swap_area;
356 error = copy_from_user(&swap_area, (void __user *)arg,
357 sizeof(struct resume_swap_area));
364 * User space encodes device types as two-byte values,
365 * so we need to recode them
367 swdev = new_decode_dev(swap_area.dev);
369 offset = swap_area.offset;
370 data->swap = swap_type_of(swdev, offset, NULL);
385 unlock_device_hotplug();
386 mutex_unlock(&pm_mutex);
393 struct compat_resume_swap_area {
394 compat_loff_t offset;
399 snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
401 BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
404 case SNAPSHOT_GET_IMAGE_SIZE:
405 case SNAPSHOT_AVAIL_SWAP_SIZE:
406 case SNAPSHOT_ALLOC_SWAP_PAGE: {
407 compat_loff_t __user *uoffset = compat_ptr(arg);
414 err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
416 if (!err && put_user(offset, uoffset))
421 case SNAPSHOT_CREATE_IMAGE:
422 return snapshot_ioctl(file, cmd,
423 (unsigned long) compat_ptr(arg));
425 case SNAPSHOT_SET_SWAP_AREA: {
426 struct compat_resume_swap_area __user *u_swap_area =
428 struct resume_swap_area swap_area;
432 err = get_user(swap_area.offset, &u_swap_area->offset);
433 err |= get_user(swap_area.dev, &u_swap_area->dev);
438 err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
439 (unsigned long) &swap_area);
445 return snapshot_ioctl(file, cmd, arg);
449 #endif /* CONFIG_COMPAT */
451 static const struct file_operations snapshot_fops = {
452 .open = snapshot_open,
453 .release = snapshot_release,
454 .read = snapshot_read,
455 .write = snapshot_write,
457 .unlocked_ioctl = snapshot_ioctl,
459 .compat_ioctl = snapshot_compat_ioctl,
463 static struct miscdevice snapshot_device = {
464 .minor = SNAPSHOT_MINOR,
466 .fops = &snapshot_fops,
469 static int __init snapshot_device_init(void)
471 return misc_register(&snapshot_device);
474 device_initcall(snapshot_device_init);